Project Summary To enable longitudinal studies combining rodent phenotyping assays and imaging, this proposal aims to acquire and install a combined positron emission tomography and magnetic resonance imaging system (PET/MRI) for installation within a specific pathogen free barrier vivarium at the University of California, Davis (UC Davis) Mouse Biology Program. Acquisition of a PET/MRI is a collaborative effort between two core facilities at UC Davis: the Center for Molecular and Genomic Imaging (CMGI) and the Mouse Biology Program (MBP). The MBP is the largest and most comprehensive core facility on the campus for essential mutant mouse production and phenotyping services used by biomedical researchers at UC Davis. The CMGI provides centralized infrastructure and expertise to design, conduct, and interpret in vivo imaging studies in animal models. The proposed instrument (M7 SimPET, Aspect Imaging) is a compact, dual modality, permanent low field (1T) magnet capable of simultaneous PET and MR imaging that does not require cryogenically cooled magnets. Its compact footprint and minimal infrastructure requirements enable the M7 SimPET to be integrated into the MBP primary mouse phenotyping pipeline. This is a unique opportunity to provide in vivo imaging that will enhance experimental protocols to reinforce the scientific rigor of animal studies by incorporating best practices to improve reliability and reproducibility in the context of longitudinal phenotyping without compromising the specific pathogen free (SPF) status of the animals. The system will be used to support at least 6 major users with NIH funding and a number of minor users with NIH and other funded research in diverse areas such as orthopedics/neuromuscular, neurological, cardiac, body composition, oncology, regenerative medicine and pharmacology. The system can evaluate the pharmacokinetics of a range of new diagnostic and therapeutic agents under development by UC Davis faculty in the context of a SPF facility. The M7 SimPET system will provide much needed in vivo imaging data to characterize unique mouse models with correlation to extensive in vivo phenotyping.